


Sunshine Breeding

by Night-Mare (Aoife)



Category: Katekyou Hitman Reborn!
Genre: Accelerated Pregnancy, Alternate Universe, Breeding Kink, Double Penetration in Two Holes, Exhibitionism, M/M, Mad Science, Male Pregnancy, Medical Inaccuracies, Medical Kink, Unconventional Uses for Dying Will Flames
Language: English
Status: In-Progress
Published: 2017-11-05
Updated: 2017-11-05
Packaged: 2019-01-29 20:33:52
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,386
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12638661
Author URL: https://archiveofourown.org/users/Aoife/pseuds/Night-Mare
Summary: There's been a number of discussions between Shouichi and Tsuna about logical extensions of his experiments, and appropriate subjects. Tsuna volunteers ...





	Sunshine Breeding

“Such a pretty and obliging little Sky, Tsuna." He's dizzy and exhausted from the sedative Shoichi had insisted on; that’s one of the reasons for the IV in his hand. He’s strapped down thoroughly, thick bands of leather around his limbs and that's Shoichi's voice, and he relaxes. He'd put himself in the redhead's hands, and they'd discussed this. Cool fingers stroked over his body, teasing, and he was confused for a long moment when his cock doesn't rise to attention in response, but then he remembers Shoichi’s warning about some of the things he’d been taking to make this possible. A smooth metal object, slick with lubricant presses into his body and then there was a clicking sound, and it started to spread his opening wide. "I'm going to do this nice and slowly, sweetheart. I need you wide enough open to check that you're nice and fertile, and that's going to take a little while." A finger presses against his prostate from outside, massaging it gently, and Shoichi’s sunshine warmth spreads slowly through him, tiny sparks of his Flames curling around his nerves, and spreading through his veins. It's not a quick build up like his normal orgasms, but just enough pleasure to take his attention off the painful stretch of his opening as the speculum clicked.

Shoichi’s thumb kept circling against his prostate from the outside, and the device kept clicking, stretching him wider and wider and wider. "You're doing really, really well Tsuna. A little bit wider, and then I can start work properly." A final click; if not for Shoichi’s Flames and the sedative he would be trying to get away from it; the ache from the stretch was _intensely_ uncomfortable. "There we go, Tsuna." Something probed at the entry to his womb, a thin metal object that scraped at something deep inside him gently, and then pushed deeper into his body. A second object was pushed into his passage, and then there was a quiet hum, and a screen blinked to life. Shoichi made a pleased sound. "Looking good, sweetheart. The graft has definitely taken well; I'm just going to insert the ova now, and then I'm going to fuck you full of cum, and then I'm going to use Sun Flames to encourage mitosis; we’ll have to see how much I can speed things up." He felt something - a spark of potential - moving up the thin instrument that had pierced the womb Shoichi had transplanted into his body weeks ago. "There we go. You're all prepared for this now, sweetheart. Does that IV feel okay?" He nods, and then Shoichi withdraws the instruments and the speculum from his opening, and he feels all sorts of odd. Open and empty and needy.

Then there were slick fingers smoothing lubricant over his walls, and he wants to beg for the other man's cock, but the words are like treacle in the back of his throat. Shoichi presses a lubricant covered finger to his lips, and a thick cock to his opening and he moans in pleasure as it bottoms out, touching his sore cervix. The pleasure-pain shock makes him _squeak_. It's such a different sensation from when they fuck normally; he relaxes into the fucking, enjoying it thoroughly, even though his cock isn't responding at all. Shoichi had explained why it wouldn't, but most of the explanation had gone _right_ over his head, and he was just going to enjoy this. The thumb that had rubbed against his prostate earlier, returned to rubbing over it from the outside, and more Sun Flames poured into his body, and the tingles spread, curling around him, his hands and his feet numbed, the pleasure hanging just outside of his reach. "You're going to look so good round and fat with my babies, Tsuna. So much so that _everyone_ is going to want to take their turn fucking you." The thumb presses, and Shoichi's cock bottoms out and stills and he cums around it, his body clenching, milking it, and the Sun makes an exclamation of his own and there's hot, thick cum, stinging at his sore cervix, and he whines as Shoichi withdraws his cock, and tilts the chair back.

He doesn't like the position, but he knows why he's been put in it, and the Sun makes an amused sound. "Don't worry sweetheart, I'm going to make the next hour _very_ pleasurable. Orgasms will help with everything, as will Sun Flames." A large plug was slid into his opening, and then Shoichi had his flaccid cock in his hand and was toying with it, and then there was a thin rod sliding in until it prods at a sensitive place and he swears incoherently as both the rod and plug start to vibrate softly. Shoichi twists the valve on the IV, and he can feel the cool liquid spreading through his veins, and the Sun's hands come to rest over the site of the womb. They're warm, like a sun warmed rock; almost too hot to bear, and he can feel them radiating Flames.

The pleasure swamps him, and he lays there, enjoying it, and feeling the Sun's warmth and then he feels the next sensation that he'd been warned about, and was why the large bore IV was pumping nutrient rich fluids straight into his veins. His belly started to stretch, and he whimpered, half-convinced that something would rupture or tear, but then Shoichi's hands lifted, and there was cool gel being spread over his belly, and the hum of another machine. "They've established nicely. Two separate placentas, and good blood flow, and they're big enough to _look_ like babies. Let's see if I can speed their growth up a little bit more." The warm hands pressed to his belly again and his eyes opened wide when he felt the fluttery kick of one of the twins. "There we go. I can't risk taking them any further; there's too much risk of something going wrong."

He feels stretched, and uncomfortable, and slightly nauseous, but there was a reward at the other end of this. The IV in his forearm is still cool, is still pumping the nutrients his body needs to support the twins into his body, and he reaches greedily for the Sun. Shoichi makes an amused sound, and twists the plug currently filling his opening. Presses it in and out of his body, and he whines; the plug isn't long enough or thick enough to stimulate his prostate, and the Sun had already pulled the rod out of his cock, so there was no stimulation from there. "I'm going to fuck you again, now, sweetheart. Take that tight passage of yours and use it until you forget how you ache." And then Shoichi's pressing into his body again, and he moans at the sensation. The position he's in, the weight of the twins, and their demands on his body mean that Shoichi has to force his way in, and the friction is painfully pleasurable. "So tight, Tsuna. Ryohei going to adore you like this."

The pleasure of the cock moving in his ass is strange, amplified and twisted and distorted by the presence of the twins in his belly. "I think you're about five months gone; you’ll be like this for eight weeks or so, I think, given that they’re twins. Ryohei and Hayato and I might manage to cut a little off of that , but it won't be intentional. Oh - and Dino, too if you bed him, Tsuna. Though you'll need to be _very_ well stretched for your senpai, sweetheart." He could quickly grow to crave this. Both the pleasure, and the feel of babies squirming in his belly. But they'd need to figure out another way to deliver everything the babies needed rather than by IV needle. He wanted to be able to _wriggle_.

"Dino-nii?" He gasps the question. That sounded like Shoichi had _personal_ experience of Dino’s cock, and he squirmed at the idea of the petite redhead in the other Sky’s lap impaled on a ridiculously large cock.

"You hadn't noticed the way he looks at you, sweetheart? He wants to eat you up." Shoichi's thumb pressed at his perineum, rubbing against his prostate in the same way he had earlier and Shoichi thrust in, and he yelped, cumming around the Sun’s cock, and then went limp. "Dino wants to skewer you on his big cock and _ruin_ this sweet little hole of yours, Tsuna." He's recovering already, the hormones surging through his body, and he thought the books he'd read in preparation for this had been joking about being insatiable. His Flames surged, and then wrapped themselves around the twins, and he relaxed as they accepted them and they started to burn out some of the suppressants Shoichi had had to use to make this work. One of the first signs of that was his cock deciding to perk up and participate.

"More, _please_. Shoichi. _Please_." He begged, and the Sun stroked his cock. It felt strange, especially after the rod Shoichi had fucked it with earlier, but he was too aroused to care about the slight discomfort.

"I think it's just as well I warned Ryohei, off, Tsuna. You and the twins have just about worn me out." Shoichi released his cock, and his hands wrapped around his hips, and his Science!Sun fucked into his slick tight hole like he was chasing his reward. His hands weren’t sunshine warm this time, and he tensed his muscles experimentally and Shoichi made a sound, and rammed in twice more, and he came around his Sun’s cock as his Sun filled him with more cum. Shoichi collapsed forward onto him, but he couldn’t even pet the redhead’s hair, given the way he was still strapped into the chair.

The two of them both panted, and recovered from that brilliant, bright orgasm, and then Shoichi unbuckled the restraints careful, rubbing the life back into his limbs. “Careful, sweetheart. They’re going to mess with your centre of gravity.” He took a cautious step, but his Flames helped with the balance issues. It made him giggle for a moment, thinking about Dino-nii’s clumsiness, and then Shoichi was helping him through into the lab’s antechamber, and then he was caught up in Ryohei’s arms, and there was his original Sun’s permanent sunshine warming him through despite his nakedness.

"You look EXTREMELY pretty like this, Tsuna." One of Ryohei's large hands splayed across his belly, feeling the way the babies were kicking in his belly.

"I should have _known_ this was one of your kinks, oniisan.” His Sun’s cheeks pink, and he’s being carried out of the living area, and he snuggles into the strong arms carrying him. “I don’t mind at _all_ , oniisan.” The pink tinge to Ryohei’s cheeks gets even redder, and he realises that there were _two_ kinks there. Not just his pregnancy - he decided to test that thought. “Right now, what I'd _really_ like you to do is slide that fat cock of yours into my ass and fuck me. Please, _Oniisan_." He's slick and he's open from participating in Shoichi’s experiment, and he's unbearably horny. He thought the books that Shoichi had made him read in preparation for this had been joking about this stage of pregnancy, but they hadn't been. All he wanted was someone to fuck him until he was raw and sore. Ryohei stills abruptly, and then he was being pressed against the wall, and kissed _furiously_. Definitely _two_ kinks he hadn’t known about and ones he’d have great fun with over the next few weeks.

"You're obviously feeling EXTREMELY horny, Tsuna." He was being held up, supported by one arm, and there was the sound of Ryohei’s fly being unzipped, and then there was his Sun's cock nudging against his opening, and he moaned appreciatively as his oniisan allowed him to ‘slide’ down his cock, so he had to take the full length of it in one go. One of the babies kicked in protest at being jostled, and he laughed and groaned at the same time, and the Sun's eyes widened at the sensation against his own abdomen. "Are you EXTREMELY sure that this is okay, Tsuna?"

"Oh yes. Ryo-nii." He's just a little bit wicked using that diminutive for his Sun. It drives the older teen just a little bit insane, and between that and his belly, apparently he's hitting on two of the boxer's previously unknown kinks. "I'll tell you if it stops being okay. Just fuck me, _please_." He whines in pleasure as his oniisan finally starts to thrust, a steady pattern that won't chase him towards his orgasm particularly quickly, but feels good anyway. He's just going to enjoy the friction, clenching his muscles on every other stroke, and teasing his Sun. The babies wriggle more, and he makes an amused sound at the exclamation from Ryohei and then groans as one of them manages to kick his prostate, sending a flash of pleasure up his spine. "They're well protected, Ryo-nii. My Flames are wrapped around them, and there's a thick layer of muscle between your cock and them."

"I EXTREMELY need more, Tsuna." There’s a sound behind them, but he doesn’t care. Not with his Sun bearing him down onto the floor, and his legs over his oniisan’s shoulders, and a fat cock working his ass _perfectly_. And then one of Ryohei’s hands wrapped around his cock and stroked it and he screamed his pleasure to the whole of the mansion. The babies _squirmed_ , and he twitched as they drank greedily of his oniisan’s Flames, and he had a feeling that he wasn’t going to be pregnant anywhere _near_ as long as Sho-chan had thought.  [Start Point Omake 1]

“While that was a _very_ pretty sight, Juudaime, but _you’re_ the one that made the rules about appropriate behaviour in the corridors.” Hayato’s voice. His right hand sounded amused, and he stretched, and Ryohei’s softening cock slipped from his ass. “And you’ll be _much_ more comfortable in a bed.” He has cum trickling down his legs when his Sun and his Storm help him to his feet and his cock twitches in interest at the idea of having both Hayato and Ryohei in his big Mafia Don bed. And Shoichi had mentioned Dino-nii, too. That made his passage twitch, and fuck he was going to have to make that happen.

Ryohei and Hayato support him as he stumbles down the corridor towards his suite, still naked, his cock hard as a rock, and he latches onto his Storm when he tries to leave them at the door. “Stay, Hayato-kun.” He drags Hayato into his suite with him and Ryohei makes an amused sound.

“You’re EXTREMELY insatiable, Tsu-kun.” His oniisan’s cock is hard again. He grins happily, and stumbles forward, flopping onto his bed. “And EXTREMELY pretty. Especially with my cum leaking from your little opening. Can I stuff my cock back in there, please?”

He whimpers. There’s no other word to describe the sound he makes. “Juudaime?” Hayato’s voice is concerned.

“Worked. It _worked_.”He’s giddy about that, and his twins’ Flames are intoxicating, too, now they’re manifesting.

“I can see that, Juudaime. It was still risky.” He pouted at his Storm and pushed up onto his elbows.

“If it was going to work for any of us, it was going to be me.” The babies kicked, and one of them kicked his prostate, and his cock twitches in response, a spike of pleasure up his spine. “Want you to ride my cock while _oniisan_ fucks me again. _Please_ , Hayato-kun.”

“Won’t the babies get in the way, Juudaime?” He’s tempted to roll his eyes at his Right Hand. Normally his Storm was quick to figure out how to manage something, but his state seemed to have broken Hayato’s brain.

“Point. Want to suck your cock, then, Hayato-kun.” His Storm’s brain stuttered again. “Oniisan, can you grab my pillows, please? Gonna need them to keep my weight off the dreadful duo.” It was a little bit awkward to undress his Storm with his baby belly in the way. He wanted to use his Flames, but the twins had them all wrapped around themselves. Which Shoichi had expected, but not in _quite_ such an all consuming way.

Hayato toed off his shoes, and swatted his hands away, and he flopped back down onto the bed again, and reached for his personal cell phone on his bed side table. He tapped out a message and sent it to his senpai. Shoichi had planted the idea in his head, and he had a really, really good excuse right now. All sorts of interesting extra hormones in his system. Not that he couldn’t be insatiable _anyway_ , but.

Then his Storm and his Sun were naked and he was being coaxed up onto his hands and knees, his body supported by several of the oversized pillows that he has on his bed. Ryohei takes advantage of the position to fuck him with both of his large, sunshine warm hands on his belly, and then there’s Hayato’s cock pressing against his lips and he moans as one of his oniisan’s thrusts strokes across his prostate and his Storm’s cock rocks smoothly into his mouth, and he sucks at the tip. Then he’s between the two of them, and when one’s cock drives into him, the other withdraws, and it’s _just_ what he wanted.

The babies kick in his belly again, and his Sun loses control of his Flames. His passage starts to twitch, and the orgasm unravels all of a sudden, quick, sharp pleasure that makes him buck and demand more from his Ryo-nii. He sucks on Hayato’s cock just as insistently, and he’s skewered between the two of them, both cocks buried to the root in his body as they both cum. Sun Flames pour into him with their fluids. They both pull out and he whines, and his Ryo-nii flops next to him on his bed. “Shoichi wasn’t kidding was he, Tsu-kun?” He can _hear_ the exhaustion in his Sun’s voice.

“There’s a reason. S’better than what would have happened otherwise.” He tugs at his right hand, and Hayato follows the pull, and he kisses him. “Fuck me, _please_ , Hayato-kun.”

“Insatiable.” He is. He wants more. He pushes himself up, and manages to swing his leg over Hayato’s hip, and his Storm laughed, and held his cock steady for him. He eases himself down, and then Hayato’s holding his hands up for him to brace himself against and he rides his right hand. It takes him a moment to find his rhythm, and the dreadful duo make it awkward. [Start Point Omake 2]

Hayato’s always worshipful when they fuck. And his hands press to his belly, and oh they’re sunshine warm, just like Ryohei’s and Shoichi’s and the cock in his ass is stretching him and throbbing and he purrs in delight. “ _Oh._ That feels good, Hayato-kun. Keep doing that.” The sunshine warm hands heat even further, and the cock in his ass thickens still further, and he moans, and Ryohei is behind him, supporting him, and wrapping a hand around his cock.

The babies kick, again. One of them _definitely_ has hyper intuition, he decides. That’s the third time one of them has directly kicked his prostate, sending a spike of pleasure up his spine, and he leans back against his Sun, and lets him take his weight, and enjoys Ryo-nii’s large calloused hands on his cock, stroking it. He cums, a dry, aching orgasm that’s almost enough, but not quite.

Hayato groans and the cock in his ass pulses, and he can feel the twins pulling on Cloud propagated Sun Flames from his Storm, and drinking _just_ as greedily as they had from both of his Suns. Then Hayato’s cock softens, and slips free from his body, and he has two exhausted Elements sprawled out, barely conscious on either side of him, and it _feels_ like the dreadful duo are heavier than they’d been even ten minutes earlier. Heavy enough that he has absolutely no leverage to sit up, and he shakes his head and rolls over onto his side. He’d summon Shoichi in a bit. Once he’s napped himself.

**Notes for the Chapter:**

> Omake 1 \- [Niccola/Phoca/Tsuna](http://archiveofourown.org/works/12668058/chapters/28876104) [return to text]  
> Omake 2 \- [Hayato/Ryohei/Shoichi/Tsuna](http://archiveofourown.org/works/12668058/chapters/28877907) [return to text]

**Works inspired by this one:**

  * [[Collection] Alternative Scenes for Sunshine Breeding](https://archiveofourown.org/works/12668058) by [Night-Mare (Aoife)](https://archiveofourown.org/users/Aoife/pseuds/Night-Mare)




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